It is well known that starches can be pregelled or precooked, dried and used in the preparation of instant food products. Traditional methods of preparing pregelatinized starches include drum drying, extrusion, and cooking followed by spray drying.
Other processes for production of instant starches include those described in:
Germino, U.S. Pat. No. 3,583,874 which discloses a starch composition suitable as a gelling agent in instant puddings which comprises a blend of pregelatinized, defatted starch and a granular preswollen starch having a water fluidity in a certain range.
Kuchinke, U.S. Pat. No. 3,332,785 which describes a cold setting pregelatinized starch material which is prepared by heating starch in an aqueous slurry with an organic carboxylic acid to 90.degree. to 95.degree. C. until the starch is completely gelatinized and thereafter spray drying the mixture.
Chiu, U.S. Pat. No. 4,228,199 which describes a chemically modified, pregelatinized, cold water dispersible gelling potato starch which is useful in preparing instant gelling food compositions. In the Chiu '199 patent, the modified potato starch is prepared by reacting a potato starch with a cross-linking agent to within defined Brabender Viscosity limits sufficient to provide the modified starch with gelling properties and thereafter drum drying the cross-linked starch to obtain the modified gelling potato starch product.
Chiu, U.S. Pat. Nos. 4,229,489 and 4,207,355 each describe cold water dispersible, gelling, chemically modified tapioca starch. The preparation of each of the disclosed gelling tapioca starches involves converting a tapioca starch to a specified water fluidity and reacting the starch with a cross-linking agent to within defined Brabender Viscosity limits. The modified tapioca starch described in the '489 patent is prepared by first reacting tapioca starch with cross-linking agent, acid converting the cross-linked starch and then drum drying the cross-linked and converted starch to provide a chemically modified, pregelatinized starch material with gelling properties.
In addition to the chemically modified, pregelatinized starches which have been developed for instant food systems, there is also disclosed in Mitchell, U.S. Pat. No. 4,260,642 the preparation of instant pudding starches through modification of a starch by forming an aqueous slurry containing an ungelatinized starch and an effective amount of sodium or calcium stearoyl-2-lactylate and heating the slurry to a temperature and for a period of time sufficient to gelatinize the starch. That patent discloses that the resultant modified starch possesses a smoother, creamier mouth-feel and higher sheen than does a starch pregelatinized without sodium or calcium stearoyl-2-lactylate. In one preferred embodiment of that invention, an aqueous slurry of ungelatinized starch is heated in the presence of calcium or sodium stearoyl-2-lactylate for a period of time sufficient to gelatinize the starch and to obtain whole granules uniformly swelled while minimizing bursting and undercooking of the starch granules and drying the slurry.
In view of recent trends and preference for the use of "natural" (not chemically modified) ingredients in food preparations, a starch composition which is unmodified by reaction with chemical modifiers or one which has been subjected to only a minimal amount of chemical modification or derivatization would offer several advantages for use in instant food systems. Not only would the cost of chemical modifying agents be eliminated or minimized but also there would be the inherent advantage perceived by the consumer of minimizing or eliminating the chemically modified starch ingredients in the many starch thickened food compositions which are included in the average consumer's diet.
With many instant food products, it is important to have rapid hydration or swelling of the starch granules.
Many pregelled or instant starches hydrate rapidly and acceptably in cold or cool water uses; however, when these starches are used with hot water or other hot liquids they tend to exhibit lumping of the starch and other ingredients. It is possible to reduce lumping of instant starch containing foods by screening the drum dried starches to obtain coarse particles. However, these products tend to be slow in hydrating and oftentimes fail to provide the desired effect, such as viscosity enhancement, for an instant food.
Accordingly, it is an object of the present invention to provide a cold water swelling starch composition which is useful as a thickening agent for instant food formulations.
It is a further object of the invention to provide a cold water swelling starch composition which is readily dispersible in hot liquids.
Another object is to provide a cold water swelling starch composition having little or no chemical substitution or modification which is readily dispersible in hot liquids.
Other objects and advantages of the invention will become apparent by reference to the following description.
Throughout the specification and claims all ratios and percentages are stated on a weight basis, temperatures are in degrees celsius and pressures are in KPascals over ambient unless otherwise indicated.